It is well known that motor boats which are driven by engines equipped with propellers, whether the engine is of the outboard motor variety or the inboard/outboard type, create a wake behind the boat due to the interaction of the propeller with the surrounding water and air. Although industrial concerns about cavitation relate to the intense vibrations which can cause severe mechanical damage to the surfaces of metals exposed to it, particularly the erosive effect of shock waves created by collapse of bubbles, sportsmen are concerned about the negative effects of excessive turbulence on successful fishing.
There have been numerous devices developed for dampening or reducing cavitation around boat propellers. Many relate to after market additions to the lower units of the engines which ride at or near the interface of the air and the water. Some boat engine manufacturers now provide lower units with small anticavitation plates integrally built into the engine. Sometimes there are separate trim tabs for stabilization of the lower unit, where the trim tabs may be positioned lower for submersion while the anticavitation plate is positioned higher. However, the manufacturer-provided anticavitation plates are often seen as too small to cover enough water surface area to do an adequate job and are frequently supplemented with an after-market extension or expansion of the plate.
Unfortunately, with the proliferation of various engine designs, no one single cavitation plate attachment fits all lower units. As a consequence boating and fishing stores must carry inventory of a number of different cavitation plate designs to meet customers' needs. Since suitable cavitation plates tend to be rather sizable, e.g. from about 2 to about 3 feet wide and from about 3 to about 5 feet long, they are not convenient to store and occupy considerable space. It would be desirable and advantageous if a way were discovered to provide a cavitation plate that would fit many, if not all, of the lower unit engine designs currently in use.